The automatic starting and stopping of internal combustion engines is well established in the art. Electric current is applied to a starting motor to initiate the process until the engine starts or a period of time elapses. A number of methods have been used to detect when the engine has started based on parameters such as engine speed, oil pressure, starter motor current, engine vacuum, etc. If the engine does not start within the specified time, there is a delay and then the starting process is retried a designated number of times. While most of the prior art relates to starting engines for vehicles, some also relates to starting stationary engines equipped with clutches, as in U.S. Pat. No. 4,563,987. In this situation, the engine runs for a period of time after starting to warm it up and then the clutch is engaged to start the load in motion. Automatic stopping based on time or conditions such as low oil pressure is also well established in the art. The engine is stopped by grounding an ignition system or cutting off fuel to the engine.
Most prior art devices employ clutches which are controlled by the movement of a mechanical actuator. Centrifugal devices and electric motors have been specified to move this actuator. In addition, a broad range of motion control devices is known which could be used to meet this requirement. Microprocessors have come into use in a variety of motion control situations. Electromagnetic clutches are controlled by controlling the current going to the device. Other types of clutches use pneumatic or hydraulic control.
In most situations, an engine which is set up for automatic starting and clutch engagement will also have a means of controlling the operating speed of the engine. A common means of controlling engine speed is a mechanical governor which uses springs and flyweights to position a throttle to maintain a preset speed. This arrangement has the engine set at full throttle prior to the engine being started. Often a device such as a solenoid is employed to pull the throttle back, against the force of the governor springs, to a low speed idle position for starting and warmup. If such an idle control device is present, it is released prior to attempting to put the engine under load. After warmup, with or without an idle controller, the engine is then allowed to run at the governed speed at a low power setting, or governed idle speed, since no load has yet been applied. Another means of controlling the engine is an electronic governor. The electronic governor typically calculates speed by measuring the time between pulses from one of several known types of electronic sensors and adjusts the throttle position with an actuator to maintain a preset speed. Solenoids and stepper motors are often used as throttle actuators and a variety of methods are known for mounting them on engines and linking them to throttles. Also, electronic governors are used to control fuel injectors on engines so equipped. Many electronic governors operate using a PID algorithm. Such governors require calibration data to achieve their best performance. Engines controlled by any of these means are referred to as speed-governed engines.
It is desirable to have good starting performance for engines which use automatic starting devices. The time that the starter motor can run is limited by battery capacity in most cases. Also, there is usually a need to run unattended by an operator. These units might be located in remote areas such as on oil well pumping units. It has been generally recognized that engine starting performance can be optimized by appropriately setting the throttle position and fuel mixture. However, this will usually be in conflict with the settings forced by the operation of the speed governor as the starter cranking speed will be substantially below the speed set for engine operation.
As suggested above, there are many operating parameters needed to control or enhance the automatic starting of internal combustion engines. With most engines, setting the initial throttle position and fuel mixture to particular values will greatly enhance starting performance. Starter parameters include the length of time to run the starter motor in the absence of starting, the number of starter retries, and specific values of those engine parameters previously mentioned which relate to determining if a start has occurred. After starting, an idle speed must be set. A warmup time must be designated prior to the engaging of the clutch. Certain types of clutch controls, such as in U.S. Pat. No. 5,662,553, require parameters such as engagement speed or time intervals to be specified. Electronic governors need a target speed and sometimes additional calibration data. Some of the prior art devices thus have a number of switches and settings to accommodate the adjustment of some of these parameters. This can make operation of the device complicated and subject it to tampering by unauthorized persons. Others do not offer the opportunity to change the parameters from an initial setting which can reduce their adaptability and effectiveness.
A variety of operator interfaces are known. A keyboard combined with a display is the most common. This may be a computer-type keyboard with a video display or just a few switches and indicator lights. The operator interface can also be a communication link of some sort so that the operator is at a distance. A large variety of electrical connections and communications protocols are in use. Radio links may be used for intermediate or long distances. For communications over short distances, infrared pulses can be used. Standards for infrared communication have been published by the Infrared Data Association.
It has been recognized by numerous references, including U.S. Pat. No. 4,331,880, dating back many years that it would be desirable to run oil well pumping units powered by internal combustion engines on an intermittent basis. In spite of this, such devices have not come into general use. Intermittent operation is a widespread practice for wells powered by electricity.